Directed under the pseudonym "Raymond Samuels" by Harry S. Webb, this cheap Western starred former silent screen cowboy Bob Custer. Custer plays Marshal Bruce Manning, whose fiancee, Ann Morgan (Victoria Vinton), begs him to interfere when her brother Clay (Eddie Phillips), a cattle rancher, is accused of killing a homesteader (Wally Wales). But Manning, who wants to prevent a war between the cattle ranchers and the "nesters," takes Clay into protective custody. Ann's father (Edward Cassidy) shoots Bruce in the shoulder, and Ann herself is abducted by the dead homesteader's mother, Ma Potter (Vane Calvert). Morgan rallies his men to free Ann but mistakenly shoots his own son. Dying, Clay admits to having killed an unarmed man. Mourning their respective sons, Ma Potter and Morgan agree to share the land. Ambush Valley was the first of three very low-budget Custer westerns produced by small-time Reliable Pictures.
~ Hans J. Wollstein, All Movie Guide